Give Clichy, Djourou, Fabianski and Nasri new deals. Whoever hasn't signed by mid July is sold and a replacement bought.
Tell Cesc now that he isn't going and that he'll be playing as a midfielder next season. If he makes a fuss or sulks, sell him and buy a replacement.
Then buy 2 attacking players; a winger and a forward. Plenty about that we could target and we should target the best we can afford.
A central midfielder that has some experience and can play and is good enough to displace Song.
A centre back that's physically dominant and that, ideally, has played in the Premier League.